The present invention relates to a fluid filter suitable for use in an internal combustion engine.
Conventional fluid filters are described in German Utility Model Application 299 15 841.1.
The central component is made somewhat tubular. xe2x80x9cSomewhat tubularxe2x80x9d means that a closed tube need not be provided but the central component can have openings and form a supporting mandrel known of itself or a drain mandrel likewise known of itself or a filter bypass valve likewise known of itself. In particular, provision can be made to make the central component in the shape of a combination component both as a supporting mandrel and as a drain mandrel and/or filter bypass valve.
The filter housing can be molded fixedly onto a motor housing part, cast for example, so that assembly of the filter takes place in an automobile factory for example with the filter housing provided on the motor being fitted with the remaining components of the filter supplied.
Simple and rapid assembly of the central component can be provided by means of a latching or snapping connection, with one or more projections or recesses being provided on the filter housing itself or on a component connected with the filter housing, and provided with one or more corresponding recesses or projections on the central component. In order to achieve good spring elasticity during latching, the projections and/or undercuts cannot extend around the entire circumference of the central component but only around portions of this circumference.
A rotation-resistant mounting of the central component that prevents movement around the lengthwise axis of this component ensures that latching between the central component in the filter housing is retained and the central component does not undesirably come loose from the filter housing. This rotation blocker can be ensured for example by an additional valve body which can be mounted off-center on the central component itself.
The goal of the present invention is to provide an improved filter that is economical and can be mounted quickly.
In other words, the invention proposes making a first jointly manageable assembly which comprises the lid, the filter insert, and the central component. Such a uniformly manageable assembly can be inserted simply, economically, and rapidly by machine into the filter housing. The entire installation group is rotated to screw down the lid. The central component is likewise rotationally driven by the fact that its connection with the filter insert and/or with the lid permits the transfer of certain rotational moments, for example by a clamping force between the connected parts or by connecting ribs that break if certain rotational moments are exceeded, or the like.
It is provided that, during the assembly process, the central component has its contact surfaces against or on the corresponding projections of the filter housing. The resulting rotational movement which the central component executes together with the lid ensures that the central component reaches the desired rotational position from any initial rotational position in which the central component is aligned in a definite position in terms of its rotational angular position which firstly ensures secure latching with the filter housing and also ensures that the central component is aligned in this latching position to form the desired rotational latch.
For this purpose, the central component is mounted rotatably relative to the lid around its lengthwise axis, for example by overcoming the above-mentioned clamping forces by breaking the aforementioned connecting ribs or the like. Provision can be made such that the central component is held directly on the lid or on the filter insert, whereupon the central component is mounted rotatably relative to the filter insert and/or the latter is mounted rotatably relative to the lid. In this manner a screwing movement for the lid is made possible with which it is screwed into the filter housing while at the same time the central component, resting against the projection on the filter housing side, retains its rotational angular position and does not rotate with it any further.
According to the invention, guide means are provided internally on the filter housing which serve to prevent rotation during assembly and which cooperate with the contact surfaces of the central component. These guide means ensure the correct rotational angular position of the central component during further assembly. During an additional screwing process of the lid, the central component therefore remains in its optimum rotational angular position and is merely introduced increasingly further into the filter housing because of the screwing process until the central component and the filter housing latch.
The projections which perform the rotational lock during assembly by cooperating with the contact surfaces of the central component can be formed by a nose or strip that projects into the interior of the filter housing, but the projection can also be formed by the side of a groove when the contact surface of the central component extends into this groove.
Advantageously, the rotational lock effective during operation and provided in any case, in addition to its actual goal of preventing inadvertent loosening of the central component from the filter housing while the filter is operating, can also be used to create an introduction aid or rotational lock during the assembly of the central component.
For this purpose, a projection provided on the filter housing side can be provided not only in the raised position of the filter housing in which it cooperates in the operating state of the filter with the corresponding contact surfaces of the central component. Instead, this projection on the filter housing side can be extended to the lid opening of the filter housing since the central component is usually inserted by this opening.
This extension of the projection can be made economically and also permits early contact between the contact surfaces on the central component on the one hand and the projection on the filter housing on the other hand so that the central component is reliably guided into the desired position during its assembly.